It is known to provide wind turbine rotor blades with lightning protection systems to protect them from strokes of lightning. For example, a rotor blade may be provided with a lightning receptor of an electrically conductive material. The lightning receptor may capture a strike of lightning and conduct the current through a lightning conductor cable extending in the longitudinal direction of the blade to a ground in the tower.
Generally, a wind turbine includes a plurality of blades coupled to a rotor through a hub. The rotor is mounted within a housing or nacelle, which is positioned on top of a tubular tower or base. Utility grade wind turbines (i.e. wind turbines designed to provide electrical power to a utility grid) can have large rotors (e.g., thirty or more meters in diameter). Blades on these rotors transform wind energy into a rotational torque or force that drives the rotor of one or more generators, rotationally coupled to the rotor. The rotor is supported by the tower through a bearing that includes a fixed portion coupled to a rotatable portion. The bearing is subject to a plurality of loads including the weight of the rotor, a moment load of the rotor that is cantilevered from the bearing, asymmetric loads, such as, horizontal and shears, yaw misalignment, and natural turbulence.
Typically, two shells, a suction shell and a pressure shell, are bonded together to form a wind turbine blade. Since the wind turbine blades are so large and are disposed in open areas, they attract and are often hit by lightning. Currently, each shell has one or more lightning receptors with a conductor cable or strip running the length of the blade along the inside surface of the blade. The multiple conductor cables require each of the conductor cable to be disposed along the shells in high stress areas, leaving room for errors and failure. Therefore, it would be desirous to have a single conductor cable for both shells instead of multiple conductor cables. However, access to the inside of the blade is limited after the shells are bonded, therefore it is difficult to connect the a receptor with one single conductor. Often the installer must insert their arms through the two shells while they are still in the molds, exposing themselves to the danger of one of the heavy shells falling from the mold and causing harm to the installer.
Therefore, what is needed is a method and system for providing access to the inside of the blade once the shells are bonded so that one common conductor cable may be used for the lightning receptor.